Launching and retrieving a boat at a boat ramp involves the difficult and cumbersome task of backing up a trailer attached to a towing vehicle. Often boat ramps are crowded and such maneuvering becomes even more burdensome. Also in many instances the rear wheels of a towing vehicle are exposed to the water which is undesirable. Also, to be able to launch and retrieve a trailer fully loaded requires a towing vehicle with sufficient power. If the towing vehicle does not have sufficient power, the launching and retrieving of a trailer can damage the towing vehicle.
Power dollies exist that can be attached to the hitch of a trailer but this involves the cumbersome task of stowing the dolly and attachment and disengagement of the dolly with the trailer. Other devices which are attachable to the draw bar of the trailer such as U.S. Pat. No. 4,860,841 to Sacco and U.S. Pat. No. 3,783,960 to Feliz are designed for maneuvering mobile home type trailers in a relatively small area and cannot propel a trailer up and down an inclined boat ramp. U.S. Pat. No. 3,861,482 to Stephens et al. shows a driving assembly which is attached to the draw bar of a trailer which is offset to the side and requires the operator to walk along side the trailer during operation. From the disclosure of the Stephens et al. patent it is not clear that the device is capable of propelling a loaded trailer up and down a ramp. Also, the driving means for the wheel is not submersible and thus the trailer could not be fully backed into the water. Even if the device could go under water the operator would have to walk into the water.
There exists a need for an assembly that can be attached to a trailer which enables the operator to be on the trailer while driving the trailer to impart weight to the drive wheel to increase traction. A need also exists for an assembly that can be attached and allow the trailer to be fully backed into the water. There is a need for an assembly that can be manufactured with a trailer or retrofitted onto a trailer. Such a device would be integral with the trailer and hitchable to a towing vehicle for travel over long distances. However, once at a ramp or other desired drop off area, the trailer is completely drivable independent of the towing vehicle and without the operator having to walk alongside the trailer.